The nearly $1-billion, 3.7-mile-long widening of Interstate 15 in downtown Las Vegas, dubbed Project Neon, may not have the flashy lights of the Strip, but it has its own cachet as the state of Nevada’s largest and most expensive public works project. A sweeping 2,606-ft-long, 81-ft-tall flyover bridge, portions of which were included as part of a major project phase that finished in November two months ahead of schedule, highlights the design-build project’s progression toward the halfway mark after just one year of construction.

Project Neon will improve the busiest stretch of highway in Nevada. With 300,000 vehicles daily—or one-tenth of the state population—and seeing 25,000 lane-changes per hour, the stretch of highway experiences about three auto accidents a day, says NDOT spokesman Tony Illia. Traffic through the corridor is expected to double by 2035. The upgrade will connect carpool lanes on U.S. Highway 95 to the Interstate 15 express lanes with that signature flyover bridge. The project will also create direct access carpool ramps, a new interchange called Neon Gateway, reconstruct the Charleston Boulevard interchange and extend Grand Central Parkway over the Union Pacific Railroad tracks.

Kiewit Infrastructure West Co., the general contractor under a $559.4-million design-build contract, with Atkins North America as lead designer, won a $5-million bonus for reopening a lane in each direction of U.S. 95 before Thanksgiving, two months early. The travel restrictions on U.S. 95 that became known as the Big Squeeze were necessary to make room for building the signature high occupancy vehicle (HOV) flyover bridge from southbound U.S. 95 to southbound I-15 that also accommodates northbound carpool traffic.

Approximately $250 million was spent for right-of-way acquisition.

The project additionally converts the two existing I-15 express lanes into a general purpose and HOV lane, thereby creating 22 consecutive miles of carpool lanes between I-15 and U.S. 95. The HOV lanes will give carpoolers and rapid transit vehicles to downtown Las Vegas access with the Neon Gateway interchange between Charleston Boulevard and Oakey Avenue.

Moreover, the project provided the “perfect opportunity” to install 52 active traffic management gantries, says Angelo Spata, project director of transportation alternative delivery with Atkins North America. That will include a 12.5-ft-long by 77-ft-wide gantry that will be the longest sign structure in the state.

The project will create direct off-ramp access from the new HOV lane and full interchanges with major local roads. The stretch of roadway being impacted and upgraded is the busiest in the state, with many merges and weaves that lead to crashes.

“We’re trying to reduce backups on I-15. We’re turning a half interchange into a full diamond interchange and reorienting a couple of surface streets to help make smoother connections on and off the freeway,” says Illia. “There are 300,000 visitors to downtown Las Vegas on any given weekend.”

Lighting the Neon

“This project was 20 years in the making,” notes Illia. “It was a hot potato” due to the anticipated social and economic impact to the Las Vegas valley. But faced with growing traffic and accidents, NDOT had to take action.

NDOT in 2014 scrapped plans to use a public-private partnership approach, turning instead to bond markets for financing. Higher interest rates, rising finance costs and increasing operation and maintenance expenses drove the about-face, according to project officials.

“We re-analyzed the delivery method due to federal funding uncertainty,” Rudy Malfabon, NDOT director, told ENR. “Bond market demands and competitive pricing make using bonds more affordable than originally projected. Also, bond payments are eligible for up to 95% federal reimbursement versus 64.9% with a public-private partnership.”

The state had solicited P3 request-for-proposals in mid-2013, naming three finalist teams: Kiewit Development Co. and Meridiam Infrastructure Neon LLC; Las Vegas Paving Corp. and Macquarie Capital Group Ltd.; and ACS Infrastructure Development Inc., Fengate Capital Management Ltd. and Star America Fund GP LLC.

A new RFP was issued within the following 30 days. “We’d teamed for the first time on this during the P3 pursuit, and we maintained the team,” says Allan Mills, project manager with Kiewit Infrastructure West Co. In November 2015, Kiewit’s team won the design-build job with a winning bid that had the highest technical score and lowest price. The schedule came in a year ahead of the anticipated completion with an estimated $80 million in saved costs.

The design team began work before officially winning the bid, says Spata. “We ramped up by the end of the year and achieved substantial design in February, eight months ahead of schedule.”

Initial design goals were to move local streets out of the way to widen I-15. “We could only close lanes either on US 95 or I-15,” Spata notes. Relocating MLK Boulevard out of the way of the new southbound lanes of I-15, a top priority, occurred over Labor Day weekend. “Now we are demolishing the old alignment and building the new southbound lanes off line,” says Spata. The work includes one mile of relocating utilities and drainage 200 ft to the west in an elevated alignment. One of the biggest utility pieces was a flood-control box, about 1,450 linear ft of a 20-ft by 8-ft structure and another 2,690 linear ft of double 18-ft-wide by 10-ft-high structure into the new MLK alignment, which contains calcified clay layers, says Mills. “We had to break and chip up the layers into Volkswagen Bug-size pieces.”

Spata calls the NDOT’s handling of utility relocations “the best I’ve seen in 20 years. They attended weekly meetings” with all the involved agencies in relocating 17 miles worth of utilities. Mills also credits NDOT with getting almost 200 rights-of-way parcels “turned over pretty early—ahead of schedule.”

Pushing Ahead

The job entails full reconstruction of 3.7 miles of the highway plus 12 miles of lane conversion. It also upgrades MLK Boulevard and extends another major artery, Western Avenue, into a connection with Grand Central Parkway. “We punched it all the way through,” says Illia. “It runs north-south and parallels I-15. It previously dead-ended. We connected it onto Grand Central Parkway, opening up another connection for traffic.”

Most of the new or upgraded bridge structures utilize precast concrete I-girders. For the HOV connector, the team used precast concrete California wide-flange girders, a first for Nevada, says Mills.

“We chose the California girders after comparing them to several other girder shapes,” Mills says. “From the technical side, these girders allow for increased reinforcing in the bottom flange and increased stability. The use of these girders in combination with high-performance concrete and wider girder spacing allowed us to utilize fewer girders and achieve longer spans.” One of the girders reaches 168 ft in length, the largest of its kind in the state.

However, the team actually reduced the original design length of the HOV connector, which will shorten the duration of construction, reduce long-term maintenance, improve maintenance of traffic during construction and lessen visual impacts, adds Mills. The redesign reconfigured the bridge to touch down within the median of US 95 approximately 2,000 ft sooner than the original design.

To do so, crews relocated US 95 westbound general-purpose and collector-distributor (CD) lanes to the north; the northwest direct-connect ramp to the north; and eastbound general-purpose and CD lanes to the south. Shifting the northwest ramp required removing approximately 400 ft of the existing segmental bridge and only replacing it with about 125 ft of aerial structure in its new location. “We also minimized HOV flyover overhang onto US 95 traffic below while staying within the existing right-of-way,” says Spata. “We built the HOV flyover in the middle of US 95 to avoid building over existing traffic.”

The team’s lane shifts reduced approved design exceptions for shoulder widths by nearly 3,900 ft and creates a vertical alignment design that provides a 70 mph design speed on the mainline, adds Spata. “Our design includes demolishing a portion of the existing northwest HOV connector bridge span at US 95 and MLK and building a longer span that will accommodate future MLK expansion.”

Shortening the flyover from 4,700 ft to 2,600 ft reduced construction by four months, Spata notes. “In addition, we completed the majority of the construction for US 95 in Phase 1, thus reducing impacts on US 95 for the remainder of construction.”

The Big Squeeze follows a November 2016 to February 2017 closure of I-15 connecting ramps to US 95, called Carnado. In March, the team will begin the last major closure phase, closing a lane in each direction of 1-15 for 252 days. That phase is called The Main Event.

“Let’s get ready to grumble,” says Illia with a wry smile.  

So far, however, so good. “Reaching the halfway point and taking a snapshot of the job, we are in great position to address the most critical I-15 work in 2018 and deliver the state’s largest transportation project on schedule and within budget,” says Dale Keller, senior project manager with NDOT.